Intramedullary nail fracture compression techniques: when and how to do it?

Outcomes of conservative treatment for bony mallet fingers

BACKGROUND

The treatment strategy for bony mallet fingers remains controversial. The outcomes of conservative treatment were investigated in this study. In addition, the time to bone union, and gap between the bone fragment and distal phalanx are discussed.

METHODS

The subjects were 26 patients (27 fingers) with bony mallet fingers (20 males and 6 females, mean age: 46.0 years old, the mean limitation of extension of the distal interphalangeal (DIP) joint: - 20.2°). In conservative treatment, splinting was applied for 6 weeks, followed by 2-week taping. The time to bone union, range of motion of the DIP joint, and the Crawford classification on the final follow-up were investigated. In addition, the bone fragment occupation rate was evaluated on plain radiography on the first examination. Furthermore, the gap on the first examination and after splinting. The relationship between the gap and bone union period was also investigated.

RESULTS

The mean time from injury to bone union was 170.2 days, the mean range of motion of the DIP joint was - 8.5° in extension and 60.9° in flexion, and the Crawford classification was Excellent for 22 fingers, Good for 2, Fair for 2, and Poor for 1. On the first examination, the mean bone fragment occupation rate was 44.0%. The mean gap on the first examination was 1.1 mm and this was significantly narrowed to 0.8 mm after splinting (p < 0.01). No significant correlation was noted between the time to bone union and gap on the first examination (p = 0.16), however, a significant positive correlation was noted between them after splinting (p < 0.01).

CONCLUSIONS

This study suggested that a favorable clinical outcome can be achieved by conservative treatment. Moreover, the bone union period decreased as the gap after splinting decreased, being significantly correlated.

Development and biomechanical evaluation of a new biodegradable intramedullary implant for osteosynthesis of midshaft fractures of small hollow bones

BACKGROUND

Up to date there is no intramedullary, biodegradable osteosynthesis commercially available to treat non-comminuted midshaft fractures of small hollow bones applying not only a stable osteosynthesis but an additional axial compression to the fracture site.

OBJECTIVE AND METHODS

Therefore we (1) designed different implant profiles and simulated the inner tension/volume using CAD. (2) Thereafter we manufactured a prototype with the best volume/tension-ratio using 70:30 poly-(L-lactide-co-D, L-lactide) (PLLA/PDLLA) and poly-ε-caprolactone (PCL) by injection moulding. Both materials are resorbable, licensed for medical use and show a slow degradation over at least one year. (3) The implants were tested in a universal testing machine (Zwick/RoellZ010) using a 3-point-bending-setup. (4) We compared the implants with different types of commercially available Ti6Al4V 6-hole 2, 3 mm-plates including interlocking systems (Leibinger Set, Stryker) (each group n= 6) using a 4-point-bending-test-setup with artificial metacarpal bones (Sawbones®).

RESULTS

The 3-point-bending-test-results showed that mean failure-force of PCL-tubes was 57.94 ± 4.28 N whereas the PLLA/PDLLA-tubes had an approximately four-fold higher value of 227.24 ± 1.87 N (p< 0.001). Additionally, the 4-point-bending-test-results showed that the maximum load of PLLA/PDLLA tubes (61.97 ± 3.58 N) was significantly higher than the strongest 6-hole metacarpal plate (22.81 ± 0.76 N) (p< 0.001).

CONCLUSION

The study showed that the new type of biodegradable, intramedullary tension-osteosynthesis made of PLLA/PDLLA is even more stable than common plate osteosynthesis in a small-hallow-bone-model. Further in vivo investigation should be performed to evaluate the surgical technique and long-term healing process of the bone and biodegradation process of the implant.

A NEWLY DESIGNED ASSEMBLY LOCKING COMPRESSION PLATE TO TREAT COMMINUTED FRACTURES OF THE FEMORAL SHAFT: A BIOMECHANICAL STUDY

The aim of this paper is to compare the biomechanical characteristics of a newly designed assembly locking compression plate (NALCP) and traditional locking compression plate (LCP) for internal fixation of femoral-shaft comminuted fractures. A femoral-shaft wedge fracture model (AO classification 32-C2.1) was created in six pairs of femoral specimens ([Formula: see text]) randomly divided into two equal groups. Biomechanical properties were tested with axial and torsional loading tests. The relative maximum displacement of fracture blocks and strain was recorded. A strain diagram was made; the fatigue test results of NALCP specimens under axial load were recorded. Under axial load, the relative maximum displacement of fracture blocks in the [Formula: see text], [Formula: see text], and [Formula: see text] axes was smaller in NALCP specimens than in LCP specimens ([Formula: see text] and 0.01, respectively). Under torsional load, the relative maximum displacement of fracture blocks in the [Formula: see text] and [Formula: see text] axes in NALCP specimens was less than that in LCP specimens ([Formula: see text]) but no statistically significant difference in the [Formula: see text] axes ([Formula: see text]) was found. In both cases, the main NALCP strain was higher than the LCP strain ([Formula: see text]) but no statistically significant difference in mean strain ([Formula: see text]) was found. Our NALCP provides strong mechanical stability for comminuted femoral fractures and can effectively avoid stress concentration, reduce stress shielding, and facilitate bone healing.

Intramedullary tibial nailing of distal tibiofibular fractures: additional fibular fixation or not?

INTRODUCTION

The anatomy of the distal tibia accounts for reduced biomechanical stability and higher complication rates when treating distal tibiofibular fractures with an intramedullary tibia nail (IMTN). The goal of this study was to identify variables that affect the stability of IMTN. We assessed the value of additional fibular fixation, angular stable interlocking screws (ASLS) and multiplanar screw configuration in IMTN.

PATIENTS AND METHODS

A retrospective cohort study was performed including 184 distal tibial fractures and associated fibula fracture treated with IMTN. Relevant demographic, fracture-related (type and level of the tibia and fibula fracture) and operative variables (depth of the nail, screw type and configuration, use of polar screws, fibular fixation) were studied. Coronal and sagittal alignment was assessed directly and 3-6 months after IMTN. Loss of reduction (LOR) was classified as 5-9° or ≥10°.

RESULTS

48.4% of the patients showed ≥5° LOR in one or both planes. Coronal LOR 5°-9° significantly correlated with low tibial fractures (p = 0.034), AO/OTA type 43 distal tibial fractures (p = 0.049), and sagittal LOR 5°-9° (p = 0.015). Although sagittal LOR 5°-9° was associated with fibular fractures (non-fixated suprasyndesmotic, p = 0.011), conversely we could not demonstrate the added value of (suprasyndesmotic) fibula fixation in IMTN. Coronal LOR ≥10° significantly correlated with AO/OTA type 43 distal tibial fractures (p = 0.009). In contrast to multiplanar configuration, we found a clear benefit of ASLS in distal IMTN locking.

CONCLUSIONS

The level of the tibial fracture (AO/OTA type) and (suprasyndesmotic) fibular fractures were the main determinants of LOR after IMTN. ASLS was found to increase the stability of IMTN. Due to heterogeneity, however, we could not demonstrate the value of fibular fixation in IMTN. Therefore, a future prospective study with uniform treatment strategy for IMTN of distal tibiofibular fractures, with or without fixation of the fibula, is mandatory.

Expandable Proximal Femoral Nails (EPFNs) in Elderly Patients

PURPOSE

The purpose was to study the performance of expandable proximal femoral nails (EPFNs) for the treatment of unstable intertrochanteric fractures in elderly patients.

PATIENTS AND METHODS

Eighty-four patients were treated with a newly designed EPFN and followed up for one year.

RESULTS

The mean operating time was 50.1 ± 3.2 min and the mean blood loss was 112.3 ± 5.3 ml. Patients were treated with EPFNs of 220 mm (n = 24), 240 mm (n = 59), and 340 mm (n = 1) length. At six months postoperatively, the Harris Hip Score was 74.5 ± 5.3. At the end of follow up, 75% of patients completely recovered their preoperative function and resumed their normal activities. Seven patients died within one year postoperatively. During the operation, one patient experienced proximal femoral diaphyseal slight crack fracture. This crack fracture was treated by using a long EPFN (340 mm). Two patient developed screw cut-outs, which were solved by reoperation. And one developed deep infection resolved favorably by the appropriate antibiotic treatment. Implant failure, deep venous thrombosis, fat embolism, secondary fracture, and nonunion were not encountered.

CONCLUSIONS

In conclusion, the results of the EPFNs were satisfactory in most elderly patients with unstable intertrochanteric fracture. However, during the inflation period, the pressure on the nail must be monitored carefully in order to prevent a crack fracture.